Ever participated or cheered someone on during a marathon only to see everyone donning shiny silver capes at the end? While we think that everyone who participates in a race is a superhero, there’s actually a super practical reason for the metallic towels. SCIENCE IS AWESOME!

What Are Those Foil Wrappers At the Marathon?

They warm you up. Physicians and fitness experts say the HeatSheets, as they are known, serve an important function for runners who compete in cool-weather marathons. Marathoners don these sheets for the same reason campers and hikers pack them as survival equipment, and for the same reason they are a staple ofemergency medical-supply kits: They help prevent hypothermia by reflecting body heat.

Runners tend to shed layers of clothing as they progress in a race, with most finishing in shorts and a shirt. The best way to keep cool is to sweat, but marathoners typically can’t perspire very well due to dehydration. Long-distance runners find it difficult to take in more liquids than they lose through sweating. As they become more dehydrated over the 26.2-mile course, it becomes more difficult for the body to cool. Consequently, the body’s core temperature rises.

After runners cross the finish line, their internal sensors tell their bodies to keep shedding heat. In the meantime, when external temperatures are cool, runners will lose body heat rapidly because their heads, legs, and arms are exposed. (It was down in the 40s for yesterday’s race.) Under these conditions, runners completing a marathon can run the risk of venting off too much heat and becoming hypothermic.

HeatSheets are designed to combat this problem. They are made by taking sheets of Mylar, a polyester film developed by DuPont in the early 1950s, and coating them with a thin veneer of aluminum. If the sheet is wrapped around a body, the aluminum coating allows the material to reflect heat and capture it in an envelope around the skin. Since they’re lightweight, HeatSheets are easier to store and hand out to large groups of people than, say, sweatshirts. And since they’re nonabsorbent, they won’t retain water on rainy days. The wrappers are designed to enable runners to cool down gradually until they can find some dry clothes and fluids.

For the sake of experiment, the Explainer yesterday ran about 205 minutes through the streets of New York. Upon finishing, he donned a HeatSheet and stumbled toward Central Park West. He felt many things: intense pain, relief, burning hunger, thirst, exhilaration, and exhaustion. But no chills.

Pedal With More PowerResearchers have found that just one month of plyometric training (jumping exercises) twice a week can increase your power endurance by 17 percent. This means you’ll be stomping out longer sprints and charging up hills in your big ring. Try squat jumps twice a week: Stand with feet shoulder-width apart, arms at sides. Sit into a squat, lowering until your thighs are parallel to the floor. Jump explosively and reach for the ceiling. Land gently and lower into another squat. Do two sets of 10.

Climb Smarter: Choose a gear you can spin in, not mash.

(Illustration by Dale Murray)

Climb SmarterChoose a gear you can spin, not mash, since anything in the steep zone puts you at risk of exploding.Visualize pedaling across the stroke rather than simply up and down. Strive to apply power horizontally through the bottom and top of the stroke.When out of the saddle, if you feel your body bobbing too much, shift one gear harder. If you feel like you are excessively swinging your bike from side to side, shift one gear easier.

Sprint in WinterTry not to jam so much saddle time into the cold months that you’re torched by June. Instead, add power sprints— 5- to 10-second all-out efforts—to your riding, says Neal Henderson, founder of Boulder-based APEX Coaching. “You’ll add quality to compensate for what you aren’t doing in quantity, without overdoing it.”

Stay SharpDon’t cram in miles the week before an event or race. Keep your rides short, so your body can be rested and ready.

Avoid the Dead Zone: Vary your training to realize gains.

(Illustration by Colin McSherry)

Avoid the Dead ZoneThis condition, common among cyclists, is brought on by repeated training at a single, moderately hard intensity (the orange line in the example at right). It afflicts enthusiasts who push the pedals hard but don’t follow a training program, as well as amateur racers who have the great Eddy Merckx’s famous maxim, “ride lots,” indelibly burned into their brains. Those suffering from the malady may not be aware of it. That’s because, at a minimum, it maintains fitness, says Henderson. “You’re working kind of hard, but not doing a lot to change your physiology.” In order for your body to adapt and improve, you need to follow a program that hits the extremes, he says, especially the high end.

Eat on the Clock: Set reminders so that you will not forget to eat and drink on longer rides.

(Illustration by Dale Murray)

Eat on the ClockOn long rides, it’s easy to lose track of how much time has passed since you last ate or drank. One easy solution: Set reminders on your watch, phone, or bike computer for regular intervals. For example, every 10 to 15 minutes drink 4 to 6 ounces of water or sports drink; and every 15 to 20 minutes (after 45 minutes of riding), eat 7 to 10 grams of carbohydrates.

A Case for CooldownA study in the Journal of Strength and Conditioning Research found that when cyclists did a 15-minute cool-down spin at 30 percent of their maximum VO2 after a hard effort, they were able to perform almost as well 24 hours later on an identical strenuous workout.

Gain Free SpeedScoot your butt back on the saddle and ride with your hands in the drops. (If you have a flat bar, scooting back and bending your elbows will still lower your profile, making you more aerodynamic.)On descents, tuck your elbows and knees in toward your bike and lower your head as much as possible while still maintaining control.If you need just one bottle, put it in the cage on your seat tube, which is slightly more aero, instead of on your down tube.When you’re riding in street shoes, tuck your laces inside instead of letting them flap—every millisecond counts, right?

Last-Minute Century Training PlanYour plan was to be triple-digit fit by April. Now that 100-miler you registered for light-years ago is just a month away, and you’ve barely cracked 40. Do this century crash course (only if your fitness base already includes a few rides a week), and you’ll be ready to roll.

Shoot for 65Coaches advise that you should do a 75-mile ride before your century. But you can squeak by with a long ride of 65 miles.

One Steady, One Speed, One SpinRide three or four days a week between now and the event: Ride long one day and at a fast pace another, with at least one easy-spin day in between. On your fast ride, try this: Warm up for 20 minutes, ride fast for 20, cool down for 20. Inch up the mileage on your easy rides by a mile or two as you progress toward the event. Follow our full-century training plan.

Go to Bed Already!When you sleep, your body produces hormones that are critical to recovery. Research has shown that getting just two fewer hours of sleep than normal can slow your reaction time, an extra level of risk you don’t want when you’re navigating in traffic or a tight pack. It’s also a factor in performance, says Stanford University sleep researcher Cheri Mahf. In 2011, Mahf and her colleagues found that when athletes who were sleeping 6 to 8 hours a night aimed for closer to 10 hours, their reaction time and performance improved.

Get a Killer Jump: Practice standing starts in a big gear (53×19) for 20 to 30 pedal strokes.

(Illustration by Dale Murray)

Get a Killer JumpPractice standing starts: Using a big gear such as 53×19, roll to a slow speed, then accelerate at 100 percent effort as fast as possible for 20 to 30 pedal strokes. Begin with three or four sprints and build to six or seven. The first three pedal strokes are the most important; this is when the “sprint” message is transferred from your brain to the muscle fibers. Take the first stroke with your dominant leg, starting with the pedal at a two o’clock position.

Roll With ItThe world would be a better place if we all had the luxury of a daily postride massage. With a foam roller you can pretty much do the job yourself— minus the harp music. “As you roll a muscle back and forth on the dense foam cylinder, adhesions and scar tissue break down,” says Scott Levin, MD, sports medicine specialist at Somers Orthopaedic Surgery and Sports Medicine Group in New York City. “It also warms and stretches muscles, increases circulation, and prevents soreness.”

Know your RHRThat’s your resting heart rate—taken in the morning before you get out of bed— and it’s one of the best ways to monitor overtraining. If your beats per minute are 10 percent higher than normal, that could be a warning that you may need to back off and take an easy day.

Maintain a Healthy Cycling WeightEat Breakfast—It keeps your energy steady, so you’re less likely to overeat later in the day.Weigh In—The vast majority of people who stay slim step onto a scale at least once a week— those concrete numbers staring up at you are simply too hard to ignore.Be Consistent—Most folks who keep the pounds off do so by staying the course. They eat well most of the time without swinging between deprivation and binges.

Reward YourselfGiving yourself strategic incentives for positive behavior can prevent backsliding. Choose healthy incentives, such as a new jersey or gloves, rather than unhealthy options like, say, cake.

Learn more about these tips and tons more essential advice on how to ride faster, get stronger, recover smarter, shed pounds, and take your riding to the next level in The BICYCLING Big Book of Trainingedited by Danielle Kosecki, $22,rodalestore.com.

Set a goal for every ride, even if the goal is recovery.

Join Team AsanaStudy volunteers reported 79 percent less lower-back pain three months after they took a weekly yoga class for 16 weeks, according to the journal Pain.

What can you accomplish in 100 days? After reaching a peak weight of 348 pounds and suffering from depression and low self-esteem, San Francisco resident LaKeisha Shurn decided to turn her life around. She joined the #giveit100 challenge with the specific goal of hitting the gym every day for 100 days. Her journey wasn’t just about losing weight—she resolved to improve her confidence and learn to love herself, flaws and all.

She posted daily videos on the #giveit100 website and at the end of her challenge, compiled a timelapse video that shows her struggles, triumphs, and a whole lot of sweat.

Over the 100 days, LaKeisha lost 18 pounds and two dress sizes, but more importantly, she also went from depressed to happy and hopeful, and from feeling helpless to empowered. Inspired by her own transformation, she extended her goal to a full 365-day challenge.

Everybody is different. Whether you’re used to running marathons or 2 miles, chances are, you’ve had that urge to stop and walk to let everything get re-adjusted. Here’s why walking while you’re running doesn’t make you any less of a real runner.

When a runner friend suggested I run my first distance race by adding walk breaks, the idea startled me. I didn’t think you were allowed to walk in races, not if you wanted to be a real runner. But the thought of running in New Jersey, all the way to the boardwalk in North Wildwood from Cape May in a single clip, seemed impossible, and I came around.

When I lined up at the start line of the Ocean Drive 10 Miler on that sharp cold morning in 2008, I shimmered with nerves. But I did have a plan: Run for nine minutes, walk one minute, run another nine minutes, walk one, and repeat, for 10 miles up the coast — even if I felt silly stopping to walk so soon into the race.

At about Mile 4, the course goes over a toll bridge, and I charged up the steep incline. One the way down, though, I hit my next walk break, and slowed down to a crawl.

“You run up the bridge but walk down?” an older man chided as he ran by.

“It’s all part of my plan!” I shouted back over a howling wind, still not entirely comfortable with my chosen course of action.

But it worked. I made my way through Cape May and over the marshes that connect it to the island just north, which held the finish line.

I gave up on the run-walk-run plan soon after that first distance race. In 2009, I took on the Ocean Drive 10 challenge again, cutting out the walk breaks and beating my time by more than 16 minutes. I felt like a champion, a real runner, and vowed to run all my races going forward, especially when I made the leap to the marathon, because I thought that’s what real runners do.

But out of the five marathons I’ve run, I’ve walked in four — and never by choice. In those races, I started too fast, taxed my legs too soon, and fell back into a forced run-walk-run around Mile 20 as a way to just to get to the finish line. I felt humiliated as spectators goaded me on. “You’re almost there!” they’d shout, but I but I wanted to spit at them. They didn’t know my pain, standing on the sidelines with their earmuffs and coffees and handwritten signs. Six miles isn’t almost there, I’d tell myself self-pityingly as I hobbled onward.

In those four marathons, when I should have been charging the finish line in a blaze of glory with my hands thrown triumphantly over my head, instead I dragged myself across the final timing mats. A shroud of failure hung over me during those races and for weeks after, a sense that I wasn’t a real runner, that I had given up.

Now I’m ready to embrace walking again. A study in the Journal of Science and Medicine in Sport found that including regular walking breaks in your race can bring you to the finish line at the same pace as if you ran the entire way — while doing a lot less damage to your body.

The study looked at 42 runners who trained 12 weeks for their first marathons. A week before the event, the runners were split evenly into two groups: those who would run the entire way and those who would take 60 second walking breaks every 2.5 kilometers.

The walk breakers performed well. Runners in both groups finished the marathon with similar times and the group that took walking breaks experienced less muscle pain and fatigue after the race than their running-only counterparts.

“Most people think that if you walk in a marathon race, you will need much more time to finish,” said Kuno Hottenrott, a professor of sports science at the Martin Luther University of Halle-Wittenberg in Germany and lead author of the study. Even he was surprised by the results.

But the benefits of intermittent walking goes beyond the physical, he says. “Since running a marathon is as much of physical as well as a mental challenge, it is for a runner mentally easier to break the marathon distance down into smaller parts and focus on one segment at a time, instead of looking at the whole marathon distance.”

Jeff Galloway, the running coach and Olympian runner, pioneered the run-walk-run method in the mid-1970s. He added walks to his beginner students’ training because he saw that it helped them run farther and for longer periods of time than if they tried to plow through the distance just running, with fewer injuries. “It allows each person to gain control over their running,” he says. “They get to set the amount of running and the amount of walking, and they can feel good on every single running segment.”

More than 300,000 people have used the Galloway Run Walk Run Method, he says, with the fastest marathon time reported back to him from a 30-something male student who dropped his marathon time to 2 hours 28 minutes, from 2 hours 33 minutes, by adding walking breaks.

This weekend, I will be undertaking the Gasparilla Challenge, a series of races in Tampa, Fla., that include a 15K and 5K on Saturday and a half marathon and 8K on Sunday. It’s a lot of work, and I know my legs will feel like telephone poles at the end. But the only thing I’m really anxious about is a potentially hot weekend.

Why? Because to get through more than 30 miles in two days, I’ve returned to that proven strategy: nine minutes of running, followed by one minute of walking. Repeat. Repeat. Repeat.

Jen A. Miller is the author of “Running: A Love Story,” to be published by Seal Press in spring 2016.

MapMyFitness has folks working all over the United States but the majority of our team is proud to call Austin home. Here’s what took place this past weekend during the Austin Marathon. If this doesn’t inspire you to finish your neighborhood run, we don’t know what will.

Hyvon Ngetich of Kenya appeared to be headed to an overwhelming victory at the Austin Marathon when she was suddenly running on empty, and then she wasn’t running at all.

In the final 50 meters of Sunday’s race, Ngetich dropped to her hands and knees and began crawling to the finish line, so depleted that she came to a complete halt more than once during her crawl. Marathon personnel hovered behind her with a wheelchair to provide Ngetich with assistance, but she persisted and crossed the line in 3:04:02, still good for third place.

“I was like winning, you know. I was 500 [meters] in front. I looked back and I didn’t see anybody,” Ngetich said in a report carried by KTBC and other media outlets. “For the last two kilometers, I don’t remember,” added the Kenyan, who won the 2011 Santiago Marathon in Chile in 2:34:42. One woman on a bicycle told her she was nearly at the finish “so I was just like going because I’m almost” done, said Ngetich.

Austin Marathon Director John Conley said, “When she came around the corner on her hands and knees, I have never, in 43 years of being involved in this sport, have seen a finish like that.”

The Austin victory and $3,000 went to Texas-based Kenyan Cynthia Jerop. Hannah Steffan of Austin passed the prostrate Ngetich right before the race’s end and bested her by three seconds in 3:03:59, worth $2,000. Third place would customarily be worth $1,000, but Conley said he’d upgrade her prize money to the $2,000 she would have gotten for second place.

Guacamole is a good start, but it’s certainly not the only way to get your avocado fix. In fact, you can substitute avocado into many of your favorite dishes.

It’s no wonder avocado has been crowned “America’s new favorite fruit.” Below, find seven ways to swap avocado for several less wholesome ingredients to amplify just about any recipe’s nutritional stats.

Mayonnaise

Mayonnaise perfectly binds dishes like tuna, egg and chicken salad, but it’s full of unhealthy fats and pretty much void of nutritional value. Choose avocado instead; it can pull off mayonnaise’s gluing powers while adding its healthy super powers, and it won’t interfere much with the taste and texture you crave.

You might also make an avocado spread and use it as a condiment to replace mayo on your turkey sandwiches. To make it, just mash a bit of avocado and add a drop of olive oil if the mashing is difficult.

Cheese

Before you scream, “anything but cheese!” hear us out. On a sandwich, most cheeses add a nice contrast to the bread, vegetables and fillers, and avocado will do just that. Cut the cheese and you’ll also cut the cholesterol and salt.

Butter

This is kind of miraculous: You can replace the butter in a cake with avocado. Doing this will nix the saturated fat (bad) for monounsaturated fat (good). Avocado can be substituted for butter in a 1:1 ratio, but you’ll need to adjust the recipe’s other ingredients a bit so that the baked good comes out moist enough. See these tips from The Kitchn for detailed instructions.

Sour Cream

If you’re used to adding a dollop of sour cream to your soups or rely on it for the creamy base of your dips, consider swapping it for avocado. You’ll get that same delightful consistency, but the mix will be dairy-free and full of nutrients.

Cream & Milk

Want a really creamy smoothie? A luscious pudding? Add avocado. Its texture enriches all types of sweet treats, and its neutral taste won’t get in the way of dessert.

Bread

OK, so an avocado doesn’t really mimic the texture or taste of bread, but it’s a mighty fine alternative for anyone looking to beef up nutrition come mealtime. You can bake an egg inside an avocado or use the fruit as a bowl to cradle your tuna salad.

Ice Cream

Wild, right? To be completely candid, avocado ice cream probably won’t satisfy your dairy craving when you really want it. In cases like this, we say have the ice cream. But, when a frozen, creamy treat is singing your song and you’re hoping for something healthier, turn to the trusty avocado.

Kale is good for you. Really, really good for you. But man cannot live on kale alone. While it has stolen the power food spotlight in recent years, there’s so many other wonderful veggies just waiting for you to take them home and turn them into something glorious. Check out this piece on some produce rockstars from the Huffington Post.

Or maybe you didn’t like it all that much to begin with? Either way, the trendy super-green has definitely had its 15 minutes of fame, and then some: Just recently, health-conscious New Yorkers getting ready for the big storm freaked out when stores ran out of kale. This, after rumors of a shortage last year were all over the news, even inspiring a parody. Some people have even been naming their children Kale. (And you thought Apple was a weird name.)

All this is to say that our kale obsession has gotten way out of hand. Note: there are lots of other vegetables with nutritional super powers. Here are some to try.

Bok Choy

If you want to stick with leafy greens, give bok choy a chance. This Asian green is “very rich in calcium, a decent source of iron and magnesium and very high in vitamins A and C,” Aynsley Kirshenbaum, MS, a Brooklyn-based nutritionist and personal trainer, tells Health. “To absorb the vitamin A, pair it with some fat. A cold-pressed sesame oil with garlic would be delicious.” Tip: the smoke point of sesame oil is really low, so cook the bok choy and garlic with a little bit of olive or coconut oil. Then drizzle with sesame oil right before removing the skillet from the heat.

Another great choice is Swiss chard, which is also rich in vitamins A and C, as well as vitamin E and minerals such as iron and calcium, Kirshenbaum says. Basically, it has all the nutrition you need, and adds a pungent, almost salty flavor. “Plus, it’s easily interchangeable with kale in recipes, so you can keep the other ingredients the same and have a fresh new take on your favorite meals,” she adds.

Savoy Cabbage

Nick Saltmarsh/Flickr

Cabbage is a fantastic green, very high in vitamins C and K. Try purple cabbage for a shot of color in a salad, or add shredded savoy cabbage to a stir fry. For something different, look for real, fermented sauerkraut at farmer’s markets and health-food stores. Since it’s fermented, you’ll get even more of the abundant nutrients in the cabbage. (Be sure the label says it’s fermented; you don’t get the benefits from the regular kind sold in jars in supermarkets.)

Give good ol’ fashioned collard greens a second look. They’re nutritionally similar to kale, rich in minerals and vitamins A, C, and K. I love to use them to make wraps. Simply cut the stems off and slice out the tough spines, then submerge the leaves one at a time in a large skillet of simmering, salted water for about 30 seconds. Remove the leaves and place in a bowl of ice water to stop the cooking. Carefully pat the leaves dry with clean kitchen towels. Then fill with your favorite sandwich or burrito fillings and wrap up as you would a tortilla. Delicious, filling and great if you have a gluten intolerance or you’re simply trying to sneak in more veggies.

If you want to go beyond leafy greens for your vegetable fix, consider cauliflower. This cruciferous vegetable is a cousin to broccoli, Brussels sprouts and the bok choy we mentioned earlier (and kale, too). It’s loaded with vitamins C and K, and may help ward off cancer. Find it bland? That’s actually a plus: Its neutral flavor makes it versatile. I love it roasted; just cut into florets, toss with oil, season with salt and pepper, spread on a baking sheet and roast at 400ºF for about 30 minutes, or until browned, stirring once or twice (or roast the whole, unchopped head for a dramatic presentation). It also makes a great mash, in place of potatoes.

Beets

Muffet/Flickr

On the sweeter side are beets, which bring minerals like potassium and manganese as well as folic acid, vitamin C and fiber. That bright red color tells you they’re brimming with antioxidants. Plus, they may help bolster memory and concentration (and who couldn’t use that?). If they come with greens attached, don’t throw those out! You can chop and sauté the leaves with garlic for a quick side dish. For the beets themselves, you can’t go wrong with roasting (the same way you would the cauliflower). Or you can shred them raw, mix with shredded carrots and a dressing for a quick, refreshing salad. Make your own dressing by mixing olive oil, orange juice and/or cider vinegar, a bit of grated ginger and salt and pepper. Finally, don’t feel bad buying these pre-roasted and vacuum-sealed from at the supermarket as a shortcut and just tossing them into a green salad.